Fistulas are a major cause of morbidity and mortality, as there are over one hundred thousand cases of pathologic fistulas a year, which account for over ten thousand deaths. They cost the healthcare system billions of dollars each year to treat.
Fistulas are tissue-lined connections between body cavities and hollow organs or between such cavities or organs and the surface of the body. The fistula tract includes a void in the soft tissues extending from a primary fistula opening to a blind ending or leading to one or more secondary fistula openings. Fistulas frequently develop as a consequence of infections or accompany abscess formations. Although some fistulas are purposely created for therapeutic purposes such as tracheostomy tracts, gastric feeding tube tracts, or arteriovenous fistulas for dialysis access, pathological fistulas are abnormal tracts that typically occur either congenitally or form after surgery, surgery-related complications, or trauma. They are most often open tracts that have epithelialized, endothelialized, or mucosalized.
Fistulas can form between almost any two-organ systems, or multiple organs, or between different locations of the same organ. For example, they may occur between internal organs and skin (enterocutaneous fistulas, gastrocutaneous fistulas, anal fistulas, rectovaginal fistulas, colocutaneous fistulas, vesiclocutaneous fistulas, intestinocutaneous fistulas, tracheocutaneous fistulas, bronchocutaneous fistulas, etc.) or between internal organs themselves (tracheal-esophageal fistulas, gastrointestinal fistulas, colovesicular fistulas, palatal fistulas, etc.). Anal or anorectal fistulas connect the anus and the rectum, and tend to be relatively short. Fistulas may also form between blood vessels such as arteriovenous fistulas.
Although fistulas may form in many locations in the body, they are almost universally highly morbid to patients and difficult for clinicians to treat. Some treatment options may include surgery, while other treatment options may include implantable devices designed to aid in the closure of the fistula. These devices, however, may cause adverse immunological reactions in patients, may allow leakage of fluid around them, or may result in contamination of the fistula tract. There is a need in the art for an implantable device for closing a fistula that reduces the chance of adverse immunological reactions, and the leakage of fluid through the fistula tract, and that has a reduced likelihood of contaminating the fistula tract during use.